Could I serve a cold soup in cold weather? Menu is pork tenderloin with balsamic glaze, roast veggies , and green rice.... Suggestions very

Twenty years ago I had a delicious plum soup in Prague. It was probably laced with a little Slivovitz. It was not cold, but cool. Plums would go nicely with pork and the roast veggies. I am sure there are plenty of recipes online if you want to investigate.

wonderful idea, but spouse in on a kidney diet....no potatoes!

How about Vichyssoise? The leeks and potatoes make it autumnal. If you change your mind it's easy to heat up.

I don't know why you couldn't, but I'm curious what about the above menu - very appetizing, I might add - would make you think "cold soup?"

I love cold soups, and often make them in warm weather, but would be perfectly fine eating one anytime. Hot soup on a cold night is a western cultural norm, but if you’re inclined to do a cold one, I wouldn’t worry much about ‘rules’. Moreover, many cold soups are actually better served at room temp (flavors mute when ice cold, especially with creamy ones). Also, a cold - room temp - soup can be nice with a hot garnish – e.g., puree of cauliflower with sauteed shrimp/scallops, or tomato with warm croutons/cheese or hot bacon crumbles, and so on. Maybe that mediates the cold/hot issue a little.

It's not traditional, but in my mind, if my friend is making me pork tenderloin with blasamic glaze, roast vegetables and green rice, I'm already totally winning. I think as long as you believe the meal works together, go for it. I also wear white after Labor Day and am going to give my entire family botulism by playing fast and loose with cooling french onion soup so you maybe should let saner heads prevail! :)

A personal reaction to a menu adding cold soup to a hearty main and sides you mentioned is that the menu (and diner expectations) would be off balance.
Cold soup signals (to me) light and refreshing, especially in its common forms like gazpacho and central European fruit soups. Not what most of us are looking for or wanting as we transition to (or actually have) cool autumn weather.
If you are really keen to serve it, though, try as part of a pre-dinner cocktail service in shot glasses with a selection of canapes, where it might fit better.
Then serve your planned meal at table.

Could you? Sure, nothing stops you.

Should you? Well, that's just a personal preference call. Personally, I don't care too much for cold soups in general (even in summer). Whether or not you and/or your dinner guests will enjoy a cold soup course in cold weather is really relevant to your group.

Curiously, this doesn't seem to be an issue with many other courses, like salad or dessert. People seem to be happy enjoying ice cream-based dishes or other cold desserts (creme brulee) in the winter, so my guess is that temperature-related associations between food item and air temperature are largely in peoples' heads.

It's worth pointing out that the English drink tea in hot places (like India), although in that situation, the tea causes people to perspire, which promotes cooling.

Anyhow, it's your call based on your diners.

I don't see why not. This one looks good: http://www.foodandwine.com/recipes/chilled-fennel-grapefruit-veloute-with-lemon-olive-oil